Referring to FIGS. 10 to 12 or a Taiwanese patent, No. M374432, a conventional brake base comprises a cover (50), and a upper end thereof has two inlet holes (501)(502) are configured to be respectively penetrated by two brake wires and to engage with two connecting sleeves (51)(52) respectively. Two sliding surfaces (503)(504) are respectively formed at two lateral inner surfaces of the cover (50), and an interior space of the cover (50) is configured to install a sliding frame (60). Moreover, two outlet holes (505)(506) formed at a bottom portion of the cover (50) are configured to be penetrated by two adjusting bolts (53)(54) respectively. Two parallel planes (601)(602) respectively formed at two lateral ends of the sliding frame (60) are configured to respectively couple with the sliding surfaces (503)(504). Furthermore, the sliding frame (60) comprises two screw holes (603)(604) which are configured to be penetrated by two fixing bolts (61)(62), and the fixing bolts (61)(62) are configure to engage with two fixing nuts (63)(64) respectively after penetrating through the screw holes (603)(604). In addition, two block surface (605)(606) respectively formed at two sides of a central portion of the sliding frame (60) are configured to block a operating lever (70). Also, a fixing hole (607) is formed at a lower portion of the sliding frame (60), and a central portion of the operating lever (70) comprises a central hole (701). As a result, a mounting bolt (65) is configured to sequentially penetrate through the fixing hole (607) and the central hole (701), thus securing the sliding frame (60) with the operating lever (70) through a mounting bolt (65). Wherein a central portion of the operating lever (70) has a central hole (701) which is configured to be penetrated by the mounting bolt (65), thus connecting the sliding frame (60) with the operating lever (70). Moreover, a first housing slot (702) and a second housing slot (703) are respectively formed at two lateral sides of the central hole (701).
According to the components mentioned above, the cover (50) has the two inlet hole (501)(502) which are respectively engaged with the two connecting sleeves (51)(52) configured to be penetrated by a left brake outer tube (80) and a right brake outer tube (81) respectively. Wherein left steel wire (801) and right steel wire (811) respectively penetrating through interior spaces of the left brake outer tube (80) and the right brake outer tube (81) respectively penetrate through two through holes (611)(621) respectively formed on the fixing bolts (61)(62) and are firmly secured by the fixing nuts (63)(64). Two head portions of the left steel wire (801) and right steel wire (811) are respectively engaged with a left brake lever and a right brake lever. The two outlet holes (505)(506) formed at the bottom portion of the cover (50) are configured to be penetrated by the two adjusting bolts (53)(54) and be secured by two screw nuts (55)(56) respectively. Then, a front brake outer tube (82) and a rear brake outer tube (83) are respectively positioned inside two lower portions of the two adjusting bolts (53)(54), and a front steel wire (821) and a rear steel wire (831) respectively penetrate through two interior spaces of the front brake outer tube (82) and the rear brake outer tube (83). Thereafter, two head portions of the front steel wire (821) and the rear steel wire (831) are respectively positioned and coupled inside the first housing slot (702) and the second housing slot (703) of the operating lever (70), and two tail portions of the front steel wire (821) and the rear steel wire (831) are respectively coupled with a front brake and a rear brake.
When the right brake lever is pulled, the right steel wire (811) is driven to pull the sliding frame (60), the mounting bolt (65), and operating lever (70), and then the rear steel wire (831) and the front steel wire (821) are concurrently driven by the operating lever (70), thus allowing the front and rear brake to brake a front and rear wheels concurrently. Moreover, a lever arm between the first housing slot (702) and the central hole (701) is longer than a lever arm between the second housing slot (703) and the central hole (701), thus allowing the operating lever (70) to output more force to the rear brake. As a result, when the right brake lever is fully pulled, the rear brake is configured to stop the rear wheel before the front brake stops the front wheel, thus increasing safety of use for a cyclist. Moreover, the left brake lever has the same effect as the right brake lever to prevent accidents.
However, the conventional bicycle brake apparatus is disadvantageous because: the left steel wire (801) and the right steel wire (811) are configured to pull the sliding frame (60) upwardly at eccentric positions such that the sliding frame (60) is tilted during the pulling process. Since the two planes (601)(602) are configured to bear against the two sliding surfaces (503)(504) of the cover (50) respectively, the tilted motions of the sliding frame (60) are configured to lead the sliding frame (60) to excessively rub against the inner surfaces of the cover, thus affecting the function of the bicycle brake apparatus and increasing accident risks. Therefore, there remains a need for a new and improved design for a bicycle brake assisting apparatus to overcome the problems presented above.